79 450sl... chugging, sputtering, and problems accelerating! - Page 2 - Mercedes-Benz Forum

Reply
 
LinkBack Thread Tools Display Modes
post #11 of 22 (permalink) Old 09-23-2006, 07:12 PM
BenzWorld Junior Member
 
Date registered: Apr 2006
Vehicle: 1983 380SL
Location: Jersey Boy
Posts: 17
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Here's an interesting discovery in my problem: The stalling, sputtering no power problem completely disappears when I fill up the tank. As long as the tank is more than 1/4 full, I'm OK - runs like a dream. At about 1/4 it starts happenning infrequently but then as the gas level in the tank continues to drop, it gets really bad.

Now I know there is supposed to be a certain amount of tank vacuum produced by these MB closed systems. Every other car I have ever owned makes a "whoosh" sound when I open the gas cap - this car - nothing at all. When I got it, it had a generic vented gas cap. Now since I know MB isn't vented, I replaced it with the correct non-vented MB cap. Did I make the problem worse by doing that? Also, assuming this tank vacuum / gas level clue is meaningful, what does this tell me? Have I stumbled upon something here or is this ongoing intermittent fuel starvation issue finally driven me crazy?
Zestieboy is offline  
Sponsored Links
Advertisement
 
post #12 of 22 (permalink) Old 09-26-2006, 03:58 PM
BenzWorld Junior Member
 
Date registered: Apr 2006
Vehicle: 1983 380SL
Location: Jersey Boy
Posts: 17
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
I've now confirmed that the fuel level is a direct clue on the problem. Three times since my last post I got the problem to start and become chronic as the gas ran down only to disappear when I re-filled the tank. I also tried using the old vented gas cap and using no cap at all and neither one had any effect. And no matter what the situation or circumstances, I NEVER hear a sound when I remove the gas cap.

It's difficult for me to explain this as an ignition problem anymore. I'm also not sure how the FPR impacts this anymore either, but I'd like to make sure by getting the problem to manifest itself and then jumpering the relay. What pins do I jumper to test the FPR once and for all?

Assuming the FPR checks out OK and that the FP and filter are new, where do we go? FP check valve, FT vent valve, accumulator, screen, damper, warmup (control pressure) regulator, fuel distibutor?

If this weren't such a PIA, I might actually be fun!

Thank you all for your excellent suggestions, time, and interest in my problem.
Ray
Zestieboy is offline  
post #13 of 22 (permalink) Old 09-26-2006, 04:30 PM
Administratoris Emeritus
 
GeeS's Avatar
 
Date registered: Aug 2002
Vehicle: 2021 SL770
Location: Fountain Hills, AZ
Posts: 44,915
Mentioned: 2 Post(s)
Quoted: 591 Post(s)
Quote:
Originally Posted by Zestieboy
I've now confirmed that the fuel level is a direct clue on the problem. Three times since my last post I got the problem to start and become chronic as the gas ran down only to disappear when I re-filled the tank. I also tried using the old vented gas cap and using no cap at all and neither one had any effect. And no matter what the situation or circumstances, I NEVER hear a sound when I remove the gas cap.

It's difficult for me to explain this as an ignition problem anymore. I'm also not sure how the FPR impacts this anymore either, but I'd like to make sure by getting the problem to manifest itself and then jumpering the relay. What pins do I jumper to test the FPR once and for all?

Assuming the FPR checks out OK and that the FP and filter are new, where do we go? FP check valve, FT vent valve, accumulator, screen, damper, warmup (control pressure) regulator, fuel distibutor?

If this weren't such a PIA, I might actually be fun!

Thank you all for your excellent suggestions, time, and interest in my problem.
Ray
Scratch the last two items and check the rest. Also, check the vapor tank just for the hell of it...

"If spending money you don't have is the height of stupidity, borrowing money to give it away is the height of insanity." -- anon
GeeS is offline  
post #14 of 22 (permalink) Old 09-27-2006, 10:40 PM
BenzWorld Junior Member
 
Date registered: Sep 2006
Vehicle: GERMAN 1977 350SLC and 1993 600sec
Location: usa
Posts: 9
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
I have a similer problem with my 77 350slc and i noticed that it runs better when I a better intake but if you can't, keep water near by to throw on the headers just alittle to cool it down and it will keep that from geting to much hot air which messes with the air fuel mixture.
leinad190 is offline  
post #15 of 22 (permalink) Old 09-17-2007, 11:59 PM
BenzWorld Junior Member
 
Date registered: Jan 2007
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
1973 450se

hi, i got a 450 se, checked the plugs, and wires, changed the cap'n rotor, ran beutifuly, but after about 2 weeks, its now sputtering, backfiring, no power, and fuel is massively leaking from the 4th cylinder exhaust manifold right where the manifold meets the block. changed the injector and no effect. all that is left that i know of is the computer which ive found from 1500 to 700 dollars, the cold start valve, or the trigger points. please help.
as well, the fuel just seems to be pumping out the exhaust right where it meets the block, but no cracks. just a bad gasket. but what could be making it do this. keep in mind this doesnt have cats or o2 sensors or too much of anything.

Last edited by ajordan002; 09-18-2007 at 12:01 AM.
ajordan002 is offline  
post #16 of 22 (permalink) Old 09-18-2007, 11:20 PM
BenzWorld Member
 
Date registered: Mar 2007
Vehicle: 1980 450slc
Location: Redmond, OR
Posts: 134
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
The K-Jetronic injection system can be incrediably frustraiting when it isn't running well. I shudder to think how much money I spent trying to find someone that can properly diagnose and repair a K-Jetronic. Needless to say I have never come across anyone that knows how to do anything but swap parts and pray. My sig says it all for me.

1980 450slc converted to MegaSquirt electronic fuel injection and couldn't be happier!

oughtsix is offline  
post #17 of 22 (permalink) Old 09-19-2007, 01:12 AM
BenzWorld Junior Member
 
Date registered: Jan 2007
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
sorry to say it, but this is actually before the k-jetronic, this is a commonrail system. as far as i know the jetronic didn't come out untill 1976
ajordan002 is offline  
post #18 of 22 (permalink) Old 09-23-2007, 01:08 PM
BenzWorld Junior Member
 
Date registered: Dec 2006
Posts: 14
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Bcd5312 View Post
This is my first time posting anything, so hopefully im doing this right

ok I've been experiencing horrible sputtering, and hesitation problems with my 450sl. it has a new fuel pump and filter on it. After the engine is warmed up it will not accelerate when you press the pedal, when it gets like this you have to pull over because it will not go over 40 or so mph; and often when i come to a stop it just shuts off, and it esp. cant go up hills when it does this- which is a problem because i live on a mt. But the strange thing is that after you wait a few minutes it will crank back up and run strong for a few miles (sputtering still a little) and then it will do it again. My mechanic can't figure out the problem. so I am in desperate need of help from anyone who can help me find out what is happening! Another mechanic i took it to before this one, replaced the catalytic converter thinking it wasnt working properly; this fixed the problem somewhat but it continued to have the same problem esp at higher speeds when i went to pass someone. i have also been researching and i think it maybe the Mass Air Flow sensor or the Air guide housing, or the throttle valve housing. I was thinking this was a problem bc it started this problem again after i cleaned the flat metal plate thing that is on the Air Flow Sensor underneath the air cleaner, and manually pushed it down to clean around it better. Would I have caused the problem by me doing this?!?!?!?! If anyone could help me that would be GREATLY appreciated! Could i have clogged st?!?!

Brad D.
1979 450SL
So I have a 78 450SL. Similar problems!! It starts but loses power after about 1/2 hr. If I drop it into nuetral at stops, it retains power. Even with the nuetral technique, it dies out after about an hour. I've done so much research.

My current situation is to replace the fuel pump relay. BUT I CAN'T LOCATE IT!! DOES ANYONE KNOW where the fuel pump relay is located on a 78' 450SL?

Here is a picture of my relays and the relay I bought from a dealer. I cannot locate this relay anywhere. I was told it is not in the picture (on another forum) but there is no other relay in this area of my car! Any help is appreciated!


A picture of my relays.


A picture of the fuel pump relay I got from my dealer.

And there is a relay that matches the size but not color of my replacement relay in the picture. In the middle left of the picture is a silver relay which has has 5 pins but doesn't state voltage and such as my replacement.

HELP!!
jnanasakti is offline  
post #19 of 22 (permalink) Old 07-25-2009, 04:27 PM
BenzWorld Junior Member
 
Date registered: Jun 2009
Posts: 22
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Fuel pump relay by chance? Check behind the battery maybe? Before you replace the relay and any relay at that: A common diagnostic aid. Place your fingers around the relay and have a buddy crank up the car. If it is clicking you are 90% sure the relay is switching.

I have a knack for this stuff.
GenBiltstein is offline  
post #20 of 22 (permalink) Old 07-25-2009, 10:20 PM
BenzWorld Junior Member
 
Date registered: Jan 2007
Posts: 5
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
It has been a long time since I've been on here but if it's loosing power after 1/2 hr and there is no pressure in the tank I would pull outthe tank and replace every hose, then I would check the FT vent valve. The valve should have two valves in it one allows pressure to go up and one allows press down. One tube should go to the tank and one should go to the engine crankcase.
ajordan002 is offline  
Sponsored Links
Advertisement
 
Reply

  Mercedes-Benz Forum > General Mercedes-Benz Forums > Vintage Mercedes-Benz

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Mercedes-Benz Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











  • Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
     
    Thread Tools
    Show Printable Version Show Printable Version
    Email this Page Email this Page
    Display Modes
    Linear Mode Linear Mode



    Posting Rules  
    You may post new threads
    You may post replies
    You may not post attachments
    You may not edit your posts

    BB code is On
    Smilies are On
    [IMG] code is On
    HTML code is Off
    Trackbacks are On
    Pingbacks are On
    Refbacks are On

     

    Title goes here

    close
    video goes here
    description goes here. Read Full Story
    For the best viewing experience please update your browser to Google Chrome